Universally Unique Identifier (as abbreviated as UUID) is identification information formed at the terminal, ensuring each terminal to be unique in the same space time. Generally speaking, UUID is generated when running for the first time after application programs are installed. More specifically, when the application programs run for the first time, the terminal invokes application programming interface (as abbreviated as API) to generate UUID according to the random numbers of API. Since the terminal includes multiple applications, and the terminal would recall the API when re-installing and re-operating each application, the obtained UUID would change, that means, UUID would change while re-installing applications. Apparently, the UUID generated is unstable in above way.